The NYT reports that an important al Qaeda suspect captured in 2002 was identified as a probable liar by the Defence Information Agency when it came to his claims that Iraq had taught al Qaeda operatives how to use biological and chemical weapons.

The report is based on newly declassified documents.

An excerpt.

The document, an intelligence report from February 2002, said it was probable that the prisoner, Ibn al-Shaykh al-Libi, “was intentionally misleading the debriefers’’ in making claims about Iraqi support for Al Qaeda’s work with illicit weapons.

The document provides the earliest and strongest indication of doubts voiced by American intelligence agencies about Mr. Libi’s credibility. Without mentioning him by name, President Bush, Vice President Dick Cheney, Colin L. Powell, then secretary of state, and other administration officials repeatedly cited Mr. Libi’s information as “credible’’ evidence that Iraq was training Al 8Qaeda members in the use of explosives and illicit weapons.

Among the first and most prominent assertions was one by Mr. Bush, who said in a major speech in Cincinnati in October 2002 that “we’ve learned that Iraq has trained Al Qaeda members in bomb making and poisons and gases.’’

The newly declassified portions of the document were made available by Senator Carl Levin of Michigan, the top Democrat on the Senate Armed Services Committee.

Mr. Levin said the new evidence of early doubts about Mr. Libi’s statements dramatized what he called the Bush administration’s misuse of prewar intelligence to try to justify the war in Iraq. That is an issue that Mr. Levin and other Senate Democrats have been seeking to emphasize, in part by calling attention to the fact that the Republican-led Senate intelligence committee has yet to deliver a promised report, first sought more than two years ago, on the use of prewar intelligence.

An administration official declined to comment on the D.I.A. report on Mr. Libi. But Senate Republicans, put on the defensive when Democrats forced a closed session of the Senate this week to discuss the issue, have been arguing that Republicans were not alone in making prewar assertions about Iraq, illicit weapons and terrorism that have since been discredited.